A man takes a woman more seriously, and regards her as marriage material, when he believes she is trustworthy and loyal.
A loyal partner always has his back and is not prone to becoming judgmental should there be major bumps along the way in their relationship.
He knows that she is the type that continues to trust and respect him even when he is struggling to make ends meet during hard times.
Hard times such as those that come with the loss of a job, leaving him with next to no income coming in.